1. Field of the Invention
The present invention relates to an improved attachment for tractors and in particular relates to a rear mounted hydraulic hoisting device attachable to a tractor and operable from the tractor hydraulic system.
2. Description of the Prior Art
The prior art contains many examples of hydraulically operated attachments connectable to tractors. However, because there is no standardization in design of tractors, serious difficulties are encountered when the same attachment is to be used with a number of different makes and models of tractors. Some of the important features which vary on the differing makes and models of tractors include the length of the draw bar lift arms, the length and size of the draw bar, the orientation of the draw bar, the type of hitch assembly, and the rear end structure of the tractors.
Many of the examples in the prior art of tractor attachments which have been designed to be mounted universally on all makes and models of tractors have been found to be extremely complex in their design, relatively quite heavy, and difficult to attach and remove from the tractors. Examples of hoist attachments of this type can be found in the Davies patent, U.S. Pat. No. 2,554,900 and the Schaich patent, U.S. Pat. No. 2,670,175. On the other hand, some of the prior art tractor attachments which do have a simplicity of design, have been found to lack sufficient structural strength to lift heavy loads.